Fixup no-progress for fetch & clone

The intent of the commit 'fetch & clone: do not output progress when
not on a tty' was to make fetching and cloning less chatty when
output was not redirected (such as in a cron job).

However, there was a serious thinko in that commit. It assumed that
the client _and_ the server got this update at the same time. But
this is obviously not the case, and therefore upload-pack died on
seeing the option "--no-progress".

This patch fixes that issue by making it a protocol option. So, until
your server is updated, you still see the progress, but once the
server has this patch, it will be quiet.

A minor issue was also fixed: when cloning, the checkout did not
heed no_progress.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-clone.sh

@@ -395,7 +395,7 @@ then
 
 	case "$no_checkout" in
 	'')
-		test "z$quiet" = z && v=-v || v=
+		test "z$quiet" = z -a "z$no_progress" = z && v=-v || v=
 		git-read-tree -m -u $v HEAD HEAD
 	esac
 fi